In a vessel used as a high-speed craft of a slim type, such as a passenger vessel and a ferry, the current flow increases at the stern when navigating in a sea speed range, which increases a negative pressure at the stern, and immersion of the stern increases accordingly. Therefore, considering from the viewpoint of the vessel resistance, it becomes in a state where the stern is exaggerated, which sharply increases the resistance of the whole vessel. This tendency is particularly prominent in a high-speed craft in which the Froude number is equal to or larger than a predetermined number (for example, 0.3).
A technique for solving such a problem has been described in Patent Literature 1 mentioned below. A transom-stern-type stern shape described in Patent Literature 1 is a hull bottom shape along the vessel centerline of a commercial vessel having a transom stern, in which an inflection point is provided at a predetermined distance from a stern end to generate a change of a flow field accompanying a change of the current speed, and a hull bottom surface inclined downward from the inflection point to the stern end is provided to generate a downward flow to form an accelerated flow region backward of the inflection point, thereby reducing the stern wave.